Straight through 3.9 EFI?

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carpy

carpy

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right, i dont often post questions coz usually with a bit of searching i can find it, but not so with this one

So i am picking up my bog standard classic 3.9 tomorrow. basically, i want it to sound a little nicer - it's a V8 afterall you may as well get the most out of it!

so firstly, how do you guys recommend getting it to sound better? some say remove the mid box, some say the rear box, some say chuck a cherrybomb on the end, others look in disgust at the mere thought of it! what do you think? how do i release the V8 thunder?

i have looked for some straight through pipes, but cant find any at all. is it a case of getting somewhere to fabricate them for you or am i being a total tit and overlooking somewhere or something obvious?

cheers in advance!
 
yes and no, you want tune resistor, mot failure if grossly noisy and long life or similar will make any type exhaust

The tune select resistor was utilized so one ECU could be used in all locations. There were several different tune select resistors depending on the location.

Red wire, 180 Ohms, Australia, Rest of world.

Green wire, 470 Ohms, UK and Europe - Non Catalyst

Yellow wire, 910 Ohms, Saudi - Non Catalyst this one if your going this root no cats etc

White wire, 3900 Ohms, USA and Europe - Catalyst
 
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yep i only want to make it burble a bit nicer, so i need to let the ECU know of this plan first and then **** around - why do computers have to be involved i mean honestly
 
what I'm suggesting is do not be tempted by expensive tuned systems-will do nothing without simple plug in tune resistor
(bulge in loom on bulkhead from memory).

branch tubular manifolds good too, depends on your requirements/budget

saw some systems from the usual popular land rover parts people that would sound nice and pass mot
 
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My 3.9 back box rusted off and I replaced it with a straight through bit of stainless pipe just to get me home and keep fumes out a few months back. Very little difference in driving noise level but a nicer sound if that makes sense. I ended up leaving it there as it really is not loud, have not done an MOT or anything like our equiv but judging on what can pass (i.e. all the tricked out honda civics we have here) I would say noise (note I say noise , not sound - it sounds grrrreatt!) is not an issue with a straight through back box. Can't say for mid box.

Same happened with my 200tdi a few years back (well, I actually caught that one on a rock) but I wasn't long replacing it, so big difference there.
 
Carpy,

Do be careful!! If you want to strike a balance between noise/comfort and no worries at MOT time then I would suggest standard back box but remove the centre box and leave everything else well alone. I ran my RRC with no centre box and a small cherry bomb at the back. Sound was shall I say agressive, not a problem if you live in the middle of nowhere and don't drive too far. It was uncomfortably loud on longer runs but using a standard back box has it about right imho.
 
I run a full Double S system. Tubular manifolds with two boxes. Sounds ok. But was a nightmare to fit. right hand header wasn't formed correctly.

good exhaust note, not that noticable from inside and passes MOT.

I did run a twin 4" rage bock box on a Rover 827 a few years back. On full throttle it sounded like an F1 car going down the home straight. You could hear it start from 3/4's of a mile away. Passed the MOT. But not sure about any new regs on that.
 
classic kev said:
Carpy,

Do be careful!! If you want to strike a balance between noise/comfort and no worries at MOT time then I would suggest standard back box but remove the centre box and leave everything else well alone. I ran my RRC with no centre box and a small cherry bomb at the back. Sound was shall I say agressive, not a problem if you live in the middle of nowhere and don't drive too far. It was uncomfortably loud on longer runs but using a standard back box has it about right imho.
Click to expand...

This may be what i go for

you lot do have to remember though that my daily driver for a good long while has been a defender 110 with a 2 inch lift, minimal to non existant sound proofing, and very aggressive mud tyres. even a crazy loud exhaust will be quieter than what i am used to -at 50mph in my defender you can hardly hear yourself think!

so standard backbox, small cherrybomb, and straight through mid box - this sounds like a decent little plan
 
On my 3.5 EFi RRC, The back box rusted through so I bought a cheap straight through back box off eBay with a 2" stainless tip for £20.

Nice burble, a bit louder than standard but not intrusive inside.
 
unless you have cats fitted you will not need to replace tune resister!
removing the centre silencer will effect the back pressure inturn dropping power and increasing noise.
i have a janspeed stainless middle and back silencer and a mild steel four branch manifolds i have also decatted it but refit them for mot
 
vougese39 said:
unless you have cats fitted you will not need to replace tune resister!
removing the centre silencer will effect the back pressure inturn dropping power and increasing noise.
i have a janspeed stainless middle and back silencer and a mild steel four branch manifolds i have also decatted it but refit them for mot
Click to expand...


I got a straight through pipe instead of the centre silencer and it pulls better and fuel economy has improved.............














.............and it sounds GREAT;)
 
I'm looking to remove the centre silencer on my Range Rover does anyone have any suggestions as to where to find a pipe?
 
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